Fluid supply system



June 2 1960 3 Sheets-Sheet 1 Original Filed Feb. s, 1959 IN V EN TOR.

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June 28, 1960 F. c. REGGIO FLUID SUPPLY SYSTEM Original Filed Feb. 3, 1939 3 Sheets-Sheet 2 INVEN TOR. a,

3 She etsSheet 5 INVENTOR.

Y F. c. REGGIO A FLUID SUPPLY sys'rsm June 28, 1960 Original Filed Feb. 3, 1959 atent 2,942,597 FLUID SUPPLY SYSTEM Ferdin'ando Carlo Reggio, P.0. Box 692, Norwalk, Conn.

Application July 30, 1952, Ser. No. 301,697, which is a division of application Ser. No. 496,296, July 27, 1943, which is a continuation of application Ser. No. 254,355,

- Feb. 3, 1939. Divided and this application June 25,

1956, Ser. No. 593,471

9 Claims. Cl. 123-140) This invention relates to variable-delivery pumps, and more particularly to pumps or other fluid discharge devices having fluid pressure operable means for varying the fluid output thereof.

The present application is a division of my copending application Serial No. 301,697 filed July 30, 1952, which is a division of application Serial No. 496,296 filed July 27, 1943, which is in turn a continuation of my application Serial No. 254,355 filed February 3, 1939. The last three cases are now abandoned.

While the invention has utility as a fluid supply system for various purposes, it is particularly useful for supplying liquid fuel to thermal or combustion engines or powerplants, and is shown and described in connection with an aircraft engine.

One of the objects ofthe invention is to provide fuel supply means particularlyadapted forautomatic control v Another object is to provide an improved variable-displacement fuel pump in combination witl ja servo-mech anism for variably regulating the rate of fuelfdelivery.

A further object of the invention isto provide'an improved fluid supply system including a plurality of fuel discharge or metering units each delive'ring fluid at the same rate.

The above and other objects of the invention will be apparent as the description proceeds; and while I have illustrated and described the preferred embodiments of the invention as they now appear to me, it will be understood that such changes may be made as fall within the scope of the appended claims. In the following description and in the claims various'details will be identified by specific names for convenience, but they are intended to be as generic in the application as the art will permit.

In the drawings:

Figure 1 is a sectional elevation of afuel metering P p; I a

Figure '2, in part a section on line 2-2 of Figure 1, shows two fuel metering pump units together with means for feeding fuel at' variable pressure thereto; and

V [Figure 3 diagrammatically indicates a fuelfmetering pump applied to an aircraft engine. H

Figure 4 is a section along line 4-4 of Figure 2.

As shown in Figure l, a fuel pump 1 has a plunger 2 reciprocating in a barrel'3 having a port 5 which is indicated in dotted lines as it :is formed in the front portion of the barrel 3." At its upper' end, beyond an annular .groove 6, the plunger 2 has edges 7, 8 which limit the plunger surface in contact with the bore of barrel 3 which cover and uncover the foot 5 as the plunger reciprocates. Below the groove 6 and at'suitabledistanc'e therefrom the plunger 1 has a splined portion 10 formed as a pinion and meshing with a rack '11 formed in a piston 12 slidable in a cylindric cavity 15 of barrel 3. The lower end of the plunger 2 is urged by a spring 16 against a lifter 18 operated by a cam 19 driven by the engine. A cup-shaped cap 20 screwed on the upper end of the barrel 3 closes the pumping chamber 22 and provides,

between barrel and cap, an annularchamber or reservoir 24 communicating through the port 5 with thepumpin'g chamber 22and through annularpassages 26' and 27 of very small area provided between barrel 3 and cap 20 with annular chambers 26 and 27 respectively." A gasket 23 preventsfuel leakage between barrel 3 and cap 20.

The annular chambers 26 and 27 communicate with a chamber 28 at one end of'the cylinder 15 by means of ducts 30, 31, 32 and 33; The chamber 29 at the opposideend'o'f thecylinderlS communicates withthe reservoir 24 through a duct 35. At the upper end of the pump chamber 22 a spring-loaded check valve 36 admits fuel, through a duct 38, an annular groove 39, a duct 40 and a hollow fastening bolt 41 to a conduit 42 leading to the nozzle. Aspring 44 acting on piston 12 is provided in chamber 28; In the preferred embodiment, a

. multicylinder engine has number of pumps 1 each arranged near'the corresponding cylinder. As indicated in Figure 2, a fuel transfer pump 48, connected through a pipe 51 with a fuel tank, not shown, delivers fuel to a conduit or manifold 45 which communicates, through a hollow bolt 43 and a duct 47 with the chamber 29 and the reservoir 24.of each pump 1, while the chamber 28 of each pump 1 communicates, through a duct 33 and another hollow bolt46, with a fuel return line 49 and a pipe 50 leading fuel back tothe tank. Between outlet and inlet ports o'f'thetransfer pump 48a by-pass'is provided, controlled by a pressure regulating valve including a piston 52 urged by a spring 53 whose load may be varied by screwingor'unscrewing the threaded cap 54 which is providedwith an actuating arm'55. A groove 56 and a duct 57 lead duel leakage back to the return line 49.

As the delivery of fuel by the transfer pump 48 is substantially'lar'ger thanthe' total requirements of the pumps lunde'rallfoperatingconditions, excess fuel is by-passed past the regulating valve 52,and the-fuel pressure in the feed line or manifold 45 and in the cylinder chambers 29 of the various pumps 1 will therefore be controlled by the load'of the valve spring 53 and in turn by the adjustment of the control lever 55. Changes of pressure in chamber 29 axially displace the piston 12 and vary the angular adjustment of the plunger 2 so as to alter the fuel discharge of the pumps 1. In Figure 3 apump 1 is shown equipping an aircraft engine 60 to which combustion air issupplied by means of .a compressorfil. A control lever 66 adjusts the angular position of lever 55 which is shown in detail in Figure 2. The fuel conduit 42 connected with the discharge port of the pump 1 communicates with a nozzle 70 through which fuel is discharged in the stream of air from the compressor 61. The nozzle 70 may obviously be mounted in any suitable position.

As shown in-Figure 1, the plunger 2 is at the end of its suction stroke and has uncovered the port 5 allowing fuel to flow into the pump space 22. As the plunger rises, operated by the cam 19, the surface comprised between edges 7, and.8 covers the port 5. The pressure rises rapidly in the space 22 and lifts the check valve 36, and

' cha'rgeoffuel continues until the edge 8 uncovers the port 5'which now functions as a pressure relief port through which the remaining fuel displaced by the plunger is bypassed into the reservoir 24.

While the engine is in operation, the fuel pressure in grooves 26 and 27, substantially the same as'in chamber 28 and in the fuel return line 49, is lower than in .the' reservoir 24, and a continuous flow of fuel is vented or bled through the annular apertures or passages of very small area 26' and 27 provided between the reservoir 24 and the grooves 26 and 27. The volume flowing through an orifice under a given difference of pressure being for a gas or a vapor several times larger than for a liquid, the area of said passages'26' and 27 may be madesuch V Patented June 28, 1960 that under the existing difference of pressure vapor or gas separating from the fuel in reservoir 24 can be eliminated therefrom, while only a comparatively small volume of liquid fuel escapes. through said passages. Since said annular passages 26 and 27 surround the port 5, whatever the orientation of the pump 1 may be relative to the vertical line, gas or. vapor bubbles can be vented from the reservoir 24 at a point higher than the port 5, thereby reducing the risk of such bubbles being drawn into the pump space 22 where they might interfere with the correct operation of the pump.

The plunger 2 being provided with atleast one sub-. stantially helical control edge, the duration of its effective delivery stroke and thereby the quantity of fuel discharged per stroke may be varied by a turning adjustment of the plunger obtained by operating the fuel pressure regulating valve 55. In the preferred embodiment of the invention the fuel supply system is so arranged that changes in fuel pressure in the manifold 45 and the corresponding variations in delivery per cycle of the pumps 1 are proportional. Owing to the fact that axial displacement of the valve 52 due to changes in the fuel flow past the valve is very small, and the spring 53 may be designed with a high rate of resiliency, the slight variations in the axial position of the valve 52 cause no appreciable change in the spring load; and it follows, therefore, that variations in the angular setting of lever 55 and the corresponding changes in the fuel delivery per cycle of the pumps 1 may also be considered proportional. Moreover, in order to secure proper venting and cooling of the pumps 1 under allconditions, the system may be so designed that the zero-delivery angular adjustment of the plunger 2 correspond to a predetermined pressure in the fuel manifold 45 higher than in the fuel return line 49, so that under all conditions a certain amount of fuel will always bleed through the pumps 1.

One of the advantages of this fuel supply system is that control of fuel delivery is obtained by adjusting the pressure regulating valve, which adjustment may be performed by automatic devices of very little energy, especially if compared with fuel pumps of the same general character in which the turning adjustment of the pump plungers is obtained by-means of links positively inter-connecting all plungers with the control means, whereby, if a plunger is scored and cannot be turned in its barrel, it may prevent the adjustment of all' other pump plungers and put the engine out of control. In the fuel supply system which is described herein, afailure occurring to one pump does; not interfere withtheoperation of the other pumps. i

It is apparent from the foregoing that the various fuel pumps or metering units 1 have their.chambers-29,'at one side of the piston 12, all connected with the fuel manifold 45, while the chambers 28, at the opposite side of the piston, are all connected to the fuel return manifold or bleed line 49. If two or more units 1 are at different elevations the absolute pressure in the various fuel chambers will vary by an amount equal to the fuel head corresponding to the difference in elevation, but within each unit 1 the variation in absolute pressure will be the same in the fuel chambers 29 and 28 whichare' located on oppositesides of the servo-piston 12, andtherefore theoperation of the piston and hence the fuel discharge ofthe metering units 1 will not be affected by variations in the relative elevation of the various units- 1. which takes place, for instance, in an aircraft engine asthe attitudeof the craft changes.

Moreover, it will be appreciated that the pressureactuated pistons 12 in the metering units-1 are compensated not only as to the effect of changes in relative elevation between the units and the corresponding variations infuel pressure due. to gravity, but also as to the effect of inertia in the fuel system due to acceleration such as occurs during aircraft maneuvers; For-instance, in a multicylinder aircraft. engineof the radial type, with the various fuel discharge units I mounted near the corresponding cylinder as indicated in Figure 3, said units would be arranged along a circle of several feet radius, that is, at considerable distance between diametrically opposed units. When theaircraft pulls out of a dive, the fuel pressure in the manifold 45' and in the chambers 29 on one side of piston 12 in the various units 1 ceases to be uniform and assumes a much higher value in the units which are on the outside of the trajectory curve of the aircraft than in the units on the. inside thereof. However, an identical. alteration of fuel pressure takes place in, the. return manifold; 49,- and; in the chambers 28 011 the opposite side of piston. 12, and therefore the various units 1 are in no way affected by the maneuver and continue to discharge fuel at the same rate.

It is to be expressly understood that the invention is not limited to the specific embodiments shown, but may be used in, various other ways, to supplyfuel or; other suitable fluid to any appropriate type of engine, on other consumer, and changes, modifications, substitutions, ad-

ditions and omissions may be made in the construction,

arrangement and manner, of operation of the parts without departing from the, limits or scope of the invention as defined in the following claims. Where the claims are dir t9- ess. all o e lem n o he. m: plete system disclosed, they are intended to cover possible uses of the recited elements in installations which may a e onz ec d. emen I claim 1.- n. a f e aies i n ys m f r.- r t rn mbu n es. he cm n tiqn. th a f e n i n. p mp ncluding reciprocable plunger means for supplying fuel under pressure to the. engine, delivery control means movable to varyithe efiective. stroke of said plunger means, a servo cylinder, and servo pistonslidable in said cylinder forpositioning said delivery control means and resiliently biased inone direction, of a second fuel pump for supplying fuel to the injection pump, a low pressure fuel system including passage means forconnectingsaid low pressure fuel system witlithe intakoof the second pump and with said servo cylinder on one side of the servo piston, con duitmeans for, connecting the discharge of the second pump with the intake; of the injection pump and with s aid servo cylinder on the opposite side of the servo piston to supply pressure fuel thereto acting on the servo piston inopposition to the resilient bias, additional passages in cluding flow-restricting orifices for bypassing fuel from said condujt means tosaid, low pressure fuel system, and valve. means controlling one at. least of said orifices for varying the amount of by-passedfuel to control the rate of engine fuel injection.

2 In a fuel injection, system for internal combustion engines, the combination with a fuel injection pump including reciprocable plunger means for supplying fuel under pressure to the engine, a. servo cylinder, a, servo piston slidable. in said cylinder, delivery control means positioned by the. servo piston for. varying the effective stroke of said plunger. means, and resilient means for biasingthe servo piston in one direction, of a. second fuel pump for supplying fuel, to the. injection pump, a low pressnre fuelfsystem. including passage means for connectingthe same with the intake. of the second pump and, with said servo. cylinder on one side of the servo piston, conduit means forconnecting the discharge of the second pump with the intakeofthe' injection pump and withsaidservopylinder on th e,. opposite side of the servo pistonto supply pressure fuel thereto acting on the servo piston in opposition to said resilient means, additional passages including flowrestricting, orifices for by-passing fuel from said conduit means to said low pressure fuel system, and valve means controlling one at least of said orifices for varying the amount of by-passedfuel and the pressure differential on said servo piston to control the rate of engine fuel supply.

3 In. afuel 'injection system for internal combustion 7 with the intake of the second pump and with said cylinder on one side of the piston, conduit means for connecting the discharge of the second pump with the intake of the injection pump and with said cylinder on the opposite side of the piston to supply pressure fuel thereto acting on the piston in opposition to said resilient means, additional passages including flow-restricting orifices for bypassing fuel from said conduit means to said low pressure fuel system, valve means controlling one at least of said orifices for varying the amount of by-passed fuel and the pressure differential on said servo piston to control the rate of engine fuel supply, and control means for positio-ning said valve means.

4. A fluid pump comprising, in combination, an intake conduit, a discharge conduit, a bleed conduit, a fluid pressure actuated control member movable to vary the flow of fluid delivered by the pump through said discharge conduit, a first chamber connected with one of said conduits for applyng fluid pressure on said control member in one direction, a second chamber connected with said bleed conduit for applying fluid pressure on said control member in the opposite direction, valve means actuated in response to variations of pressure in one of said conduits for varying the pressure in one of said chambers, and additional control means opera tively connected with said valve means for varying the adjustment thereof.

5. Fuel injection apparatus for an internal combustion engine comprising a fuel injection pump having an intake conduit, a discharge conduit, a bleed conduit for continuously removing fuel from the pump, control means movable to vary the rate at which fuel is delivered by the pump to the engine, a hydraulic cylinder, a fuel pressure actuated piston slidable in said cylinder for positioning said control means, a first chamber in said cylinder on one side of said piston and connected with one of said conduits for applying fuel pressure on said piston in one direction, a second chamber in said cylinder on the opposite side of said piston and connected with said bleed conduit for applying fuel pressure on said piston in the opposite direction, fuel pressure actuated valve means for controlling the relative fuel pressure in said first and second cylinder chambers to actuate said piston, and additional means for positioning said valve means.

6. Engine fuel supply apparatus comprising a fuel in jection pump having an intake conduit, a discharge conduit, a bleed conduit for continuouslyventing fuel from the pump, control means movable to vary the rate at which fuel is delivered by the pump to the engine, a hydraulic cylinder, a fuel pressure actuated piston slidablc in said cylinder for positioning said control means, a V first chamber in said cylinder on one side of said piston and connected with one of said conduits for applying fuel pressure on said piston in one direction, a second chamber in said cylinder on the opposite side of said piston and connected with another of said conduits for applying fuel pressure-on said piston in the opposite direction, fuel'pressure actuated valve means connected with one at least of said conduits for controlling the relative fuel pressure in said first and second cylinder chambers and thereby positioning said piston, and additional means for actuating said valve means.

7. In a fuel supply system for an internal combustion engine, a conduit for supplying fuel to the engine, a pump in said conduit adapted to discharge fuel as a function of engine speed, metering means in said conduit downstream of said pump, a by-pass around said pump upstream of said metering means, a valve in said by-pass responsive to a predetermined pump discharge pressure to control said by-pass.

8. A fuel feeding system for a multi-cylinder internal combustion engine comprising the combination with fuel injection units for receiving fuel under variable pressure and supplying fuel to the cylinders of said engineat a rate which increases or decreases upon increase or decrease of said pressure, respectively, of a conduit for supplying fuel to said fuel injection units, a pump connected to said conduit for pressurizing fuel as a function of engine speed, valve means connected with said conduit for regulating the fuel pressure therein and thereby controlling the rate of fuel supply to the engine cylinders,

passage means connected to said conduit downstream of said valve means for delivering a substantially constant quantity of fuel to said conduit upstream of said valve means, said fuel injection units delivering all of the fuel flowing in said conduit downstream of said valve means except said substantially constant quantity to the cylinders of said engine in separate and distinct charges for each cylinder.

9. A fuel feeding system for an internal combustion engine including the combination with fuel supply means for'receiving fuel under variable pressure and discharging fuel to the engine at a rate which varies with said pressure, of a conduit for supplying fuel to said fuel supply means, means connected to said conduit for pressurizing said fuel as a function of engine speed, valve means connected with said conduit for regulating the pressure of fuel in said conduit and thereby controlling the rate of fuel flow to the engine, and passage means connected to said conduit downstream of said valve means for returning a substantially constant quantity of fuel to the conduit upstream of said valve means irrespective of engine speed.

References Cited in the file of this patent UNITED STATES PATENTS 2,313,264 Reggie Mar. 9, 1943 2,612,884 Reggio Oct. 7, 1952 2,786,460 Barfod Mar. 26, 1957 

